The present invention relates to an envelope supply device and, more particularly, to an envelope feeder in an envelope insertion machine.
In a typical envelope insertion machine for mass mailing, enclosure materials are gathered in a gathering section and moved toward an inserting station where the enclosure materials are inserted into an envelope. Envelopes are separately fed to the inserting station and each envelope is placed on a platform with its flap flipped back all the way for insertion. Before envelopes are fed to the insertion station, they are usually supplied in a stack in a supply tray. Envelopes are then separated by an envelope feeder so that only one envelope at a time is moved into the inserting station. In a high-speed insertion machine, the feeder should be able to feed single envelopes at a rate of approximately 18,000 #10 envelopes per hour. At this feeding rate, it is critical that only a single envelope at a time is picked up and delivered to the insertion station.
In the past, as in the envelope feeder disclosed in U.S. Pat. No. 5,415,068 (Marzullo), envelopes are singulated by using a belt to transport the last envelope in a stack to move downstream. If one or more envelopes move along with the last envelope, it will be stopped by a mechanical retarder which provides a friction force against the moving envelope. In the envelope feeder, as disclosed in Marzullo, the envelopes are stacked vertically and the bottom of the stack is spring-loaded to allow envelopes to be separated from the top of the stack. This type of envelope feeder requires adjustments to be made to the envelope feeder or the envelope transport. Thus, while this type of top-separation design can eliminate some of the problems usually associated with pack pressure on units that rely on gravity to deliver the envelopes toward the separating device, envelope restocking is very inconvenient.
Thus, it is advantageous and desirable to provide an envelope feeder that can deliver individual envelopes at a high feeding rate and, at the same time, eliminate the above-mentioned problems and inconvenience.
According to the first aspect of the present invention, a vacuum shoe for use in a rotatable pneumatic apparatus for retrieving an item at a pickup point, wherein the pneumatic apparatus comprises an inner cylinder having an outer periphery with a least one cutout region formed therein, the inner cylinder further having an air passageway communicating with said at least one cutout region and with an air pressure device so as to provide a negative pressure to said at least one cutout region; and an outer cylinder concentrically mounted on the outer periphery of the inner cylinder for rotation, wherein the outer cylinder comprises at least one opening communicable with said at least one cutout region when said at least one opening is adjacent the pickup point while the outer cylinder is rotated relative to the inner cylinder. The vacuum shoe comprises:
a securing mechanism for removably mounting the vacuum shoe on an outer surface of the outer cylinder; and
at least one aperture communicable with said at least one opening, such that when said at least one opening of the outer cylinder is adjacent the pickup point, the negative pressure at the aperture causes the item to become attached to the vacuum shoe, allowing the pneumatic apparatus to move said item away from the pickup point.
According to the second aspect of the present invention, a rotatable pneumatic apparatus for retrieving an item at a pickup point. The pneumatic apparatus comprising:
an inner cylinder having an outer periphery with a least one cutout region formed therein, the inner cylinder further having an air passageway communicating with said at least one cutout region and with an air pressure device so as to provide a negative pressure to said at least one cutout region;
an outer cylinder concentrically mounted on the outer periphery of the inner cylinder for rotation, wherein the outer cylinder comprises at least one opening communicable with said at least one cutout region of the inner cylinder when said at least one opening is adjacent the pickup point while the outer cylinder is rotated relative to the inner cylinder;
a vacuum shoe positioned on an outer surface of the outer cylinder, the vacuum shoe having at least one aperture communicable with said at least one opening of the outer cylinder, such that when said at least one opening of the outer cylinder is adjacent the pickup point, the negative pressure at the aperture causes said item to become attached to the vacuum shoe, allowing the pneumatic apparatus to move said item away from the pickup point; and
a securing mechanism for removably securing the vacuum shoe to the outer cylinder, allowing the vacuum shoe to be removed from the pneumatic apparatus for maintenance or replacement.
Preferably, the inner cylinder is rotated independently of the outer cylinder such that when said at least one opening of the outer cylinder is rotated to a releasing point, said at least one cutout region of the inner cylinder becomes off-aligned with said at least one opening for reducing the negative pressure at the aperture of the vacuum shoe so as to allow said item to be released from the vacuum shoe at the releasing point.
Preferably, the outer cylinder is rotated along one direction, and the inner cylinder is rotated alternatively along the same direction and along an opposite direction in an oscillating motion such that said at least one cutout region of the inner cylinder alternately becomes aligned with said at least one opening of the outer cylinder for providing the negative pressure at the aperture of the vacuum shoe, and becomes off-aligned with the said at least one opening of the outer cylinder for reducing the negative pressure at the aperture of the vacuum shoe.
According to the third aspect of the present invention, an envelope feeder for feeding envelopes at a pickup point, which comprises:
a deck for supporting a stack of the envelopes;
a rotatable pneumatic feeding head for retrieving one envelope at a time from the stack, wherein the feeding head comprises an inner cylinder having an outer periphery with at least one cutout region formed therein, the inner cylinder further having an air passageway communicating with said at least one cutout region and with an air pressure device so as to provide a negative pressure to said at least one cutout region; an outer cylinder concentrically mounted on the outer periphery of the inner cylinder for rotation, wherein the outer cylinder comprises at least one opening communicable with said at least one cutout region when said at least one opening is adjacent the pickup point while the outer cylinder is rotated relative to the inner cylinder; a vacuum shoe positioned on an outer surface of the outer cylinder, the vacuum shoe having at least one aperture communicable with said at least one opening of the outer cylinder, such that when said at least one opening of the outer cylinder is adjacent the pickup point, the negative pressure at the aperture causes said envelope to become attached to the vacuum shoe, allowing the pneumatic apparatus to move said envelope away from the pickup point; and a securing mechanism for removably securing the vacuum shoe to the outer cylinder, allowing the vacuum shoe to be removed from the pneumatic apparatus for maintenance or replacement, and
a rotating mechanism, operatively connected to the feeding head, for rotating the outer cylinder relative to the inner cylinder.
Preferably, the inner cylinder is rotated independently of the outer cylinder such that when said at least one opening of the outer cylinder is rotated to a releasing point, said at least one cutout region of the inner cylinder becomes off-aligned with said at least one opening for reducing the negative pressure at the aperture of the vacuum shoe so as to allow said envelope to be released from the vacuum shoe at the releasing point.
Preferably, the outer cylinder is rotated along one direction, and the inner cylinder is rotated alternatively along the same direction and along an opposite direction in an oscillating motion such that said at least one cutout region of the inner cylinder alternately becomes aligned with said at least one opening of the outer cylinder for providing the negative pressure at the aperture of the vacuum shoe, and becomes off-aligned with the said at least one opening of the outer cylinder for reducing the negative pressure at the aperture of the vacuum shoe.
According to the present invention, the envelope feeder also comprises a strip-away plate located adjacent to the feed head for stripping away said envelope from the vacuum shoe, and a pair of take away rollers for further moving said envelope from the releasing point.
The present invention will become apparent upon reading the description taking in conjunction with FIGS. 1 to 5E.